Reference to Prior Cases
This invention relates to a prior McEathron U.S. Pat. No. 4,067,624, granted Jan. 10, 1978, which is assigned to the same assignee as the present invention and to prior patents of Hart U.S. Pat. No. 4,106,819, Hart U.S. Pat. No. 4,188,071, Wilson U.S. Pat. No. 4,033,632 and Wilson U.S. Pat. No. 3,175,276. These patents are incorporated herein by reference for a better understanding of the background of the present invention.
The present invention relates to pneumatically operated graduating release valve devices for railway vehicles, and it more particularly relates to improved graduating release valve devices for use on passenger rail vehicles.
Graduating release brake control devices currently being used on passenger rail vehicles are of the general type known as 26-C. Direct release brake control devices, however, have been improved for use on freight rail vehicles to provide improved responsiveness during brake application mode and freedom from sticking brakes on long trains during the release mode. Such a brake control device is generally known as an ABDW brake control device for freight vehicles, which is of the type generally disclosed in the Wilson U.S. Pat. No. 3,232,678, representing the well known ABD valve device, combined with a continuous quick service portion as disclosed in the Wilson U.S. Pat. No. 3,175,276.
An object of the present invention is to provide pneumatically operated graduating release valve devices for passenger rail vehicles which obviate limitations of the prior art graduating release valve devices.
Another object of the present invention is to provide improved pneumatically operated graduating release valve devices incorporating improved operating features of currently used direct release freight rail vehicle ABDW control valve devices.
Other objects, purposes, and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.